FORMATION OF DERIVATIVES OF 1,3-CYCLOHEXADIENECARBOXYLIC ACID FROM ACYCLIC ISOPRENOID α,β-ENALS AND MONOETHYL MALONATE BY THE KNOEVENAGEL REACTION

Article abstract of DOI:10.1007/BF00959577

In the presence of piperidine in toluene (110 deg C, 40 min) the reaction of 3-methyl-2-butenal, citral, or farnesal with monoethyl malonate gives, along with the esters of the respective alkenylideneacetic acids, the ethyl esters of 6-alkenyl-4-methyl-, 5,6-dialkenyl-4-methyl-, and 4,6-dialkenyl-substituted 1,3-cyclohexadienecarboxylic acids.At 2:1 aldehyde-monoethyl malonate molar ratio the secund reaction goes almost exclusively (64-90 percent yield).From the composition of the mixture of substituted 1,3-cyclohexadienes that is formed by the reaction of citral and monoethyl malonate the course of the reaction was determined.